Towards a unified terroir zoning methodology in viticulture

In viticulture, terroir is a key concept that refers to an area and thus possesses a geographical dimension. Hence, zoning of viticultural terroir is an important issue. This paper addresses soil and climate related aspects of terroir zoning. The first step of the zoning process is a clear identification of the objectives that are being pursued. Soil zoning and climate zoning methods are presented separately, although both approaches are preferably carried out simultaneously, in order to take into account soil-climate interactions in the terroir effect. Definition of a scale adapted to the objectives is critical, particularly so in soil zoning. For soil zoning, the relevance of geology, geomorphology and pedology (soil science) is discussed. The use of new technologies (e.g. GIS or remote sensing) enables the production of more detailed maps at reduced costs. In climate zoning, climate data and agroclimatic indices must be chosen according to the zoning objectives. High quality climatic data must be selected and validated. Following, homogeneous climatic zones are indentified. Viticultural zoning has to be validated, preferably so by eco-physiological studies. This paper is based on the unified terroir zoning methodology that is currently in preparation by the experts of the International Organisation of Vine and Wine (OIV).